While firearm technology has progressively developed over the years, the art has recently experienced focused advances in ergonomics and component modularity. Competitive sportsmen, tactical shooters, and recreational shooters demand innovation in these areas.
One feature that has found wide acceptance is the MIL-STD-1913 rail system (which is sometimes also referred to as a picatinny rail, or simply a rail). The MIL-STD-1913 picatinny rail is a dovetailed mounting interface having a plurality of periodically spaced ridges and slots. As is the case with all equipment defined by a Military Standard (MIL-STD) specification, the dimensions of the picatinny rail are standardized. As a result, picatinny rails and accessories configured to conform to the 1913 standard may be readily interchanged. Of importance to many shooters, since the picatinny rails utilize a repeating pattern of ridges and slots, accessories may be mounted and dismounted many times while maintaining the same orientation in space with respect to the firearm. For rifles scopes, laser designators, and this like, this allows aiming accuracy to be maintained after repeated cycles of mounting and dismounting.
The picatinny rail may be affixed to, or may form an integral structure of, a rifle receiver, rifle fore-end stock, pistol frame, or the like. Once a firearm is configured with a picatinny rail interface, accessories may be rapidly mounted by or removed by the shooter.
One common configuration of the picatinny rail system is the quad rail. Often found on AR-15 type carbines or rifles, the quad rail is a collection of four picatinny rails, mounted at the fore end of the rifle. Each of the four picatinny rails is disposed radially with respect to the rifle barrel at 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock positions. The rail at the 12 o'clock position is often at the same height over the barrel as a rail mounted at the top of the receiver. This configuration allows accessories to span, or simultaneously mount to, the receiver and the rail at the 12 o'clock position. Likewise, the remaining three sets of rails allow additional accessories to be mounted without obscuring the line of sight above the 12 o'clock rail (often occupied with a telescopic scope or other optic).
While the quad rail provides outstanding versatility with respect to receiving accessories, it was not designed from an ergonomic standpoint. Since the quad rail is often the primary contact point for a shooter's forward hand, this is a significant shortcoming. The somewhat sharp and angular edges of the picatinny rail's ridges dig into a shooter's hand upon grasping. Moreover, the pattern of protruding ridges of the picatinny rail may snag on gear and environmental objects.
Several manufacturers produce rail covers that mask the picatinny rail sections not occupied by accessories. These rail covers do not provide notable ergonomic benefits, however.
Some rail accessories provide some ergonomic benefits to discrete portions of the quad rail by adding projections therefrom. For example, the vertical fore grip (VFG) is often a projection that extends from the 6 o'clock picatinny rail at approximately ninety degrees therefrom. A shooter my either grasp the VFG with his entire hand (broom handle configuration), or may grasp the quad rail with the bulk of his hand while using the FVG to prevent undesired rearward slipping of his hand (hand-stop configuration). While the VFG does serve as a hand-stop, its projection from the quad rail interferes with several important shooting postures. For example, supporting the quad rail with a sand bag becomes extremely cumbersome, if not impossible. Also, while shooting prone, the firearm tends to rock on the contact point between the VFG and the ground (thus impairing accuracy). Further, the VFG may prevent a shooter from using objects in his environment for support, or may snag on equipment or objects used for cover or concealment.
Several products provide a ledge or ramp feature on the 6 o'clock picatinny rail to serve as a hand-stop without the substantial projection distance of the VFG. Such products only serve as a hand stop along a single rail, however, and do not reduce fatigue by providing additional support to the shooter's hand at other points around the quad rail. Moreover, prior art devices to not serve as a training aid for proper positioning of the shooter's forward hand on the firearm.
As a result, there exists a need in the art for improvements relating to how a shooter's forward hand holds a firearm.